Chemical fume hoods, when used properly, are one of the most reliable engineering controls in the laboratory. They protect workers by:
- Containing vapors, dusts, gases, and fumes generated within the hood, and removing them as air flows into the hood and then out via the laboratory exhaust system
- Contributing to laboratory ventilation as air flows through the hood
- Shielding the worker with a clear sliding window, called a sash, that contains aerosols and prevents injury from splashes, fires, or minor explosions that may occur inside the hood
Learn more about fume hoods in UW-Madison's Campus Fume Hood Policy document (PDF).
There are 2 kinds of fume hoods in use at UW:
- Constant air volume hoods: The average velocity of air entering the hood (called face velocity) should be 100 feet per minute across the face plane of the hood. EH&S tests all hoods regularly and marks the opening that gives the correct face velocity on constant air volume hoods.
- Variable air volume hoods: Some newer models, called variable air volume (VAV) hoods, modulate air flow based on sash height and maintain 100 feet per minute face velocity at all sash heights. EH&S tests VAV hoods, but does not mark the sash height since it's always 100 feet per minute.VAV fume hoods are equipped with a monitor that indicates whether the hood is in "standard operation" or "standby operation" mode. The fume hood monitor also has an "emergency purge" button, which increases airflow through the hood to maximum and can be used to quickly remove air contaminates from the lab.VAV fume hoods are equipped with flow sensors that activate an audible alarm when malfunctions occur.
UW's chemical fume hoods are inspected and tested annually by Physical Plant for functionality and condition. A certification sticker is placed on the front of each fume hood indicating the inspection results.
During certification testing, inspectors do the following:
- Check the laboratory room pressure differential (the room pressure must be negative to non-laboratory space)
- Remove old certification stickers
- Confirm the sash moves easily
- Test both the audio and visual alarms
- Confirm the face velocity is within the required specification of 100 linear feet per minute (lfm)
- Check overall fume hood condition
If you suspect your fume hood is not operating properly, contact Environment, Health & Safety at (608) 265-5000 or CARS at (608) 263-3333 for assistance.
Contracts & Purchasing
UW-Madison's Purchasing Services department offers several vendors with which to purchase fume hoods. To view fume hood contract info, peruse the links below:
Other fume hood-related products can be purchased through Shop@UW's ordering system.
Fume Hood Training
The Office of Chemical Safety offers fume hood training that covers the safe use of a fume hood, introduction to the components of a fume hood, alarms and warnings, and repair and maintenance contact info. This training is available for all UW-Madison employees who use a fume hood or have on in their work area.